Stir together coconut sugar, lime zest and juice, and cornstarch; toss with mango and transfer to prepared baking dish.
Topping: In separate bowl, stir together rolled oats, sugar, flour and coconut; using pastry cutter or two knives, cut in butter until mixture is crumbly. Sprinkle over mango mixture.
Bake for 45 to 50 minutes or until bubbly around edges and top is golden and crisp.
Tip: Serve warm with a scoop of ice cream or whipped cream. This crisp is also delicious made with peaches.